A Ca2+-sensitive cyclic-3',5'-nucleotide phosphodiesterase from sheep lung modulated by a tightly bound endogenous calmodulin.

Highly purified sheep lung cyclic-3',5'-nucleotide phosphodiesterase was sensitive to Ca2+/EGTA but insensitive to exogenous calmodulin. The Ca2+-sensitivity was inhibited by trifluoperazine. Heat-treated enzyme could activate a calmodulin-deficient phosphodiesterase, suggesting the presence of endogenous calmodulin in sheep lung cyclic-3',5'-nucleotide phosphodiesterase, possibly associated with the enzyme in a Ca2+-independent manner.

Learning dynamic prices in multiseller electronic retail markets with price sensitive customers, stochastic demands, and inventory replenishments

In this paper, we use reinforcement learning (RL) as a tool to study price dynamics in an electronic retail market consisting of two competing sellers, and price sensitive and lead time sensitive customers. Sellers, offering identical products, compete on price to satisfy stochastically arriving demands (customers), and follow standard inventory control and replenishment policies to manage their inventories. In such a generalized setting, RL techniques have not previously been applied. We consider two representative cases: 1) no information case, were none of the sellers has any information about customer queue levels, inventory levels, or prices at the competitors; and 2) partial information case, where every seller has information about the customer queue levels and inventory levels of the competitors. Sellers employ automated pricing agents, or pricebots, which use RL-based pricing algorithms to reset the prices at random intervals based on factors such as number of back orders, inventory levels, and replenishment lead times, with the objective of maximizing discounted cumulative profit. In the no information case, we show that a seller who uses Q-learning outperforms a seller who uses derivative following (DF). In the partial information case, we model the problem as a Markovian game and use actor-critic based RL to learn dynamic prices. We believe our approach to solving these problems is a new and promising way of setting dynamic prices in multiseller environments with stochastic demands, price sensitive customers, and inventory replenishments.

pH mediated delamination of anionic clay-like nickel-zinc hydroxysalt in water through intercalation of zwitterionic p-aminobenzoate ions

p-aminobenzoate could be intercalated into the anionic clay, Ni3Zn2(OH)(8)(OAc)(2)center dot 2H(2)O at a high pH (similar to 10). When the pH was reduced to similar to 7 while washing colloidal dispersion due to delamination was observed. The development of partial positive charge on the amine end of the intercalated anion causes repulsion between the layers leading to delamination and colloidal dispersion of monolayers in water. The layers could be restacked from the colloid to form the parent solid either by increasing the pH or by evaporation.

Bentsodiatsepiinien ja amfetamiinijohdannaisten seulonta virtsasta mikropilarisähkösumutusmassaspektrometrian avulla

Väärinkäytettyjen aineiden seulontaan käytetyn menetelmän tulee olla herkkä, selektiivinen, yksinkertainen, nopea ja toistettava. Työn tavoitteena oli kehittää yksinkertainen, mutta herkkä, esikäsittelymenetelmä bentsodiatsepiinien ja amfetamiinijohdannaisten kvalitatiiviseen seulomiseen virtsasta mikropilarisähkösumutussirun (μPESI) avulla, mikä tarjoaisi vaihtoehdon seulonnassa käytetyille immunologisille menetelmille, joiden herkkyys ja selektiivisyys ovat puutteellisia. Tavoitteena oli samalla tarkastella mikropilarisähkösumutussirun toimivuutta biologisten näytteiden analyysissa. Esikäsittely optimoitiin erikseen bentsodiatsepiineille ja amfetamiinijohdannaisille. Käytettyjä esikäsittelymenetelmiä olivat neste-nesteuutto, kiinteäfaasiuutto Oasis HLB-patruunalla ja ZipTip®-pipetinkärjellä sekä laimennus ja suodatus ilman uuttoa. Mittausten perusteella keskityttiin optimoimaan ZipTip®-uuttoa. Optimoinnissa tutkittavia yhdisteitä spiikattiin 0-virtsaan niiden ennaltamääritetyn raja-arvon verran, bentsodiatsepiineja 200 ng/ml ja amfetamiinijohdannaisia 300 ng/ml. Bentsodiatsepiinien kohdalla optimoitiin kutakin uuton vaihetta ja optimoinnin tuloksena näytteen pH säädettiin arvoon 5, faasi kunnostettiin asetonitriililla, tasapainotettiin ja pestiin veden (pH 5) ja asetonitriilin (10 % v/v) seoksella ja eluoitiin asetonitriilin, muurahaishapon ja veden (95:1:4 v/v/v) seoksella. Amfetamiinijohdannaisten uutossa optimoitiin näytteen ja liuottimien pH-arvoja ja tuloksena näytteen pH säädettiin arvoon 10, faasi kunnostettiin veden ja ammoniumvetykarbonaatin(pH 10, 1:1 v/v) seoksella, tasapainotettiin ja pestiin asetonitriilin ja veden (1:5 v/v) seoksella ja eluoitiin metanolilla. Optimoituja uuttoja testattiin Yhtyneet Medix Laboratorioista toimitetuilla autenttisilla virtsanäytteillä ja saatuja tuloksia verrattiin kvantitatiivisen GC/MS-analyysin tuloksiin. Bentsodiatsepiininäytteet hydrolysoitiin ennen uuttoa herkkyyden parantamiseksi. Autenttiset näytteet analysoitiin Q-TOF-laitteella Viikissä. Lisäksi hydrolysoidut bentsodiatsepiininäytteet mitattiin Yhtyneet Medix Laboratorioiden TOF-laitteella. Kehitetty menetelmä vaatii tulosten perusteella lisää optimointia toimiakseen. Ongelmana oli etenkin toistoissa ilmennyt tulosten hajonta. Manuaalista näytteensyöttöä tulisi kehittää toistettavammaksi. Autenttisten bentsodiatsepiininäytteiden analyysissa ongelmana olivat virheelliset negatiiviset tulokset ja amfetamiinijohdannaisten analyysissa virheelliset positiiviset tulokset. Virheellisiä negatiivisia tuloksia selittää menetelmän herkkyyden puute ja virheellisiä positiivisia tuloksia mittalaitteen, sirujen tai liuottimien likaantuminen.

Carbon nanotube reinforced supramolecular gels with electrically conducting, viscoelastic and near-infrared sensitive properties

Pristine and long-chain functionalized single-walled carbon nanotubes (SWNTs) were incorporated successfully in supramolecular organogels formed by an all-trans tri(p-phenylenevinylene) bis-aldoxime to give rise to new nanocomposites with interesting mechanical, thermal and electrical properties. Variable-temperature UV-vis and fluorescence spectra reveal both pristine and functionalized SWNTs promote aggregation of the gelator molecules and result in quenching of the UV-vis and fluorescence intensity. Electron microscopy and confocal microscopy show the existence of a densely packed and directionally aligned fibrous network in the resulting nanocomposites. Differential scanning calorimetry (DSC) of the composites shows that incorporation of SWNTs increases the gel formation temperature. The DSC of the xerogels of 1-SWNT composites indicates formation of different thermotropic mesophases which is also evident from polarized optical microscopy. The reinforced aggregation of the gelators on SWNT doping was reflected in the mechanical properties of the composites. Rheology of the composites demonstrates the formation of a rigid and viscoelastic solid-like assembly on SWNT incorporation. The composites from gel-SWNTs were found to be semiconducting in nature and showed enhanced electrical conductivity compared to that of the native organogel. Upon irradiation with a near IR laser at 1064 nm for 5 min it was possible to selectively induce a gel-to-sol phase transition of the nanocomposites, while irradiation for even 30 min of the native organogel under identical conditions did not cause any gel-to-sol conversion.

European aspen and hybrid aspen under changing environment : Leaf traits, growth and litter decomposition

Understanding the responses of species and ecosystems to human-induced global environmental change has become a high research priority. The main aim of this thesis was to investigate how certain environmental factors that relate to global change affect European aspen (Populus tremula), a keystone species in boreal forests, and hybrid aspen (P. tremula × P. tremuloides), cultivated in commercial plantations. The main points under consideration were the acclimatization potential of aspen through changes in leaf morphology, as well as effects on growth, leaf litter chemistry and decomposition. The thesis is based on two experiments, in which young aspen (< 1 year) were exposed either to an atmospheric pollutant [elevated ozone (O3)] or variable resource availability [water, nitrogen (N)]; and two field studies, in which mature trees (> 8 years) were growing in environments exposed to multiple environmental stress factors (roadside and urban environments). The field studies included litter decomposition experiments. The results show that young aspen, especially the native European aspen, was sensitive to O3 in terms of visible leaf injuries. Elevated O3 resulted in reduced biomass allocation to roots and accelerated leaf senescence, suggesting negative effects on growth in the long term. Water and N availability modified the frost hardening of young aspen: High N supply, especially when combined with drought, postponed the development of frost hardiness, which in turn may predispose trees to early autumn frosts. This effect was more pronounced in European aspen. The field studies showed that mature aspen acclimatized to roadside and urban environments by producing more xeromorphic leaves. Leaf morphology was also observed to vary in response to interannual climatic variation, which further indicates the ability of aspen for phenotypic plasticity. Intraspecific variation was found in several of the traits measured, although intraspecific differences in response to the abiotic factors examined were generally small throughout the studies. However, some differences between clones were found in sensitivity to O3 and the roadside environment. Aspen leaf litter decomposition was retarded in the roadside environment, but only initially. By contrast, decomposition was found to be faster in the urban than the rural environment throughout the study. The higher quality of urban litter (higher in N, lower in lignin and phenolics), as well as higher temperature, N deposition and humus pH at the urban site were factors likely to promote decay. The phenotypic plasticity combined with intraspecific variation found in the studies imply that aspen has potential for withstanding environmental changes, although some global change factors, such as rising O3 levels, may adversely affect its performance. The results also suggest that the multiple environmental changes taking place in urban areas which correspond closely with the main drivers of global change can modify ecosystem functioning by promoting litter decomposition, mediated partly by alterations in leaf litter quality.

Importance of local heating in the compaction of thermally sensitive solids

Local heating is an important parameter in compaction of thermally sensitive solids since local hot spots could conceivably raise the temperature of the system by several hundred degrees. To understand the importance of local hot spots, 20 g of ammonium perchlorate (AP) and potassium perchlorate (KP) were pressed together at 1500 kg cm−2 for 5 min. The surface structural examination of the compact revealed a secondary phase at the interfaces between the grains in the compositions ranging from 50% AP-50% KP to 10% AP-90% KP. The observation of the secondary phase only at the interfaces has been attributed to the short life times of temperature pulses present during the compaction. An interesting aspect of the investigation is the formation of a series of solid solutions of AP-KP.

Purification and properties of trehalase from the thermophilic fungus Humicola lanuginosa

Trehalase (?,?-Trehalosee gludohydrolase, EC 3.2.1.28) was partially solubilized from the thermophilic fungus Humicola lanuginosa RM-B, and purified 184-fold. The purified enzyme was optimally active at 50°C in acetate buffer at pH 5.5. It was highly specific for ?,?-trehalose and had an apparent Km = 0.4 mM at 50°C. None of the other disaccharides tested either inhibited or activated the enzyme. The molecular weight of the enzyme was around 170000. Trehalase from mycelium grown at 40 and 50°C had similar properties. The purified enzyme, in contrast to that in the crude-cell free extract, was less stable. At low concentration, purified trehalase was afforded protection against heat-inactivation by �protective factor(s)� present in mycelial extracts. The �protective factor(s)� was sensitive to proteolytic digestion. It was not diffusable and was stable to boiling for at least 30 min. Bovine serum albumin and casein also protected the enzyme from heat-inactivation.

Position-sensitive silicon strip detector characterization using particle beams

Silicon strip detectors are fast, cost-effective and have an excellent spatial resolution. They are widely used in many high-energy physics experiments. Modern high energy physics experiments impose harsh operation conditions on the detectors, e.g., of LHC experiments. The high radiation doses cause the detectors to eventually fail as a result of excessive radiation damage. This has led to a need to study radiation tolerance using various techniques. At the same time, a need to operate sensors approaching the end their lifetimes has arisen. The goal of this work is to demonstrate that novel detectors can survive the environment that is foreseen for future high-energy physics experiments. To reach this goal, measurement apparatuses are built. The devices are then used to measure the properties of irradiated detectors. The measurement data are analyzed, and conclusions are drawn. Three measurement apparatuses built as a part of this work are described: two telescopes measuring the tracks of the beam of a particle accelerator and one telescope measuring the tracks of cosmic particles. The telescopes comprise layers of reference detectors providing the reference track, slots for the devices under test, the supporting mechanics, electronics, software, and the trigger system. All three devices work. The differences between these devices are discussed. The reconstruction of the reference tracks and analysis of the device under test are presented. Traditionally, silicon detectors have produced a very clear response to the particles being measured. In the case of detectors nearing the end of their lifefimes, this is no longer true. A new method benefitting from the reference tracks to form clusters is presented. The method provides less biased results compared to the traditional analysis, especially when studying the response of heavily irradiated detectors. Means to avoid false results in demonstrating the particle-finding capabilities of a detector are also discussed. The devices and analysis methods are primarily used to study strip detectors made of Magnetic Czochralski silicon. The detectors studied were irradiated to various fluences prior to measurement. The results show that Magnetic Czochralski silicon has a good radiation tolerance and is suitable for future high-energy physics experiments.

Temperature and thiol-induced desensitization of a Ca2+-sensitive cyclic-3',5'-nucleotide phosphodiesterase from sheep lung

Ca2+-sensitivity of sheep lung cyclic-3',5'-nucleotide phosphodiesterase is provided by endogenous tightly bound calmodulin. The calcium sensitivity of a highly purified enzyme was desensitized by increasing the assay temperature. It could also be desensitized to Ca2+-activation by thiols such as dithiothreitol. The thiol-induced desensitization could be partially reversed by dialysis and almost completely reversed by dilution. The results presented in this paper indicate that thiols are possibly involved in the interaction of calmodulin with cyclic-3',5'-nucleotide phosphodiesterase. This is the first report on temperature and thiol-induced desensitization of Ca2+-sensitivity of a cyclic-3',5'-nucleotide phosphodiesterase.

Thermal reactivity of ammonium perchlorate crystallised from solutions having different pH

The thermal reactivity of ammonium perchlorate was found to be dependent on the pH of the solution from which it had been crystallised. A nitric acid-crystallised sample reacted faster than an ammonium hydroxide-crystallised one.

Organometallic derivatives of diphosphazanes. 2. Seven-coordinated Group 6 metal tricarbonyl complexes of diphosphazane ligands. X-ray crystal structure of [WI2(CO)3{P(OPh)2}2NPh]

The reactions of the complexes [MI2(CO)3-(NCMe)2] (M = Mo, W) with the diphosphazane ligands RN{P(OPh)2}2 (R = Me, Ph) in CH2Cl2 at room temperature afford new seven-coordinated complexes of the type [MI2(CO)3{P(OPh)2}2NR]. The molybdenum complexes are sensitive to air oxidation even in the solid state, whereas the tungsten complexes are more stable in the solid state and in solution. The structure of the tungsten complex [WI2(CO)3{P(OPh)2}2NPh] has been determined by single-crystal X-ray diffraction. It crystallizes in the orthorhombic system with the space group Pna 2(1), a = 19.372 (2) angstrom, b = 11.511 (1) angstrom, c = 15.581 (1) angstrom, and Z = 4. Full-matrix least-squares refinement with 3548 reflections (I > 2.5-sigma-(I)) led to final R and R(w) values of 0.036 and 0.034, respectively. The complex adopts a slightly distorted pentagonal-bypyramidal geometry rarely observed for such a type of complexes; two phosphorus atoms of the diphosphazane ligand, two iodine atoms, and a carbonyl group occupy the equatorial plane, and the other two carbonyl groups, the apical positions.

Selective sorption of ferric ion onto a crosslinked resin bearing triphenylphosphinimine residues

A polymeric sorbent containing triphenylphosphinimine residues has been obtained from crosslinked chloromethylated polystyrene by azidation, using phase-transfer catalysis, followed by reaction with triphenylphosphine at room temperature. The sorbent exhibits 100 % sorption selectivity for Fe(III) in the presence of Cu(II), Fe(II), Ni(II), Co(II), Mn(II), and Zn(II) in aqueous media. In the absence of Fe(III), however, Fe(II) is selectively sorbed over the other metal ions, and in the absence of both Fe(II) and Fe(III), Cu(II) has the highest selectivity of sorption on the resin. The sorption of Fe(III) is sensitive to pH, being maximum at pH not, vert, similar 2 and falling sharply at both higher and lower pH values. The sorbed Fe(III) is easily stripped with dilute HCl and the resulting protonated resin is regenerated to its original sorption capacity by treatment with dilute NaOH at room temperature.

Sensitive high-resolution ion microprobe U-Pb dating of prograde and retrograde ultrahigh-temperature metamorphism as exemplified by Sri Lankan granulites

Ultrahigh-temperature (UHT) granulites of the central Highland Complex, Sri Lanka, underwent some of the highest known peak temperatures of crustal metamorphism. Zircon and monazite U-Pb systems in granulites near Kandy, the highest grade region (similar to 1050 degrees C; 0.9 GPa), preserve both a record of the timing of prograde and retrograde phases of UHT metamorphism and evidence for the ages of older protolith components. Zircon grains from a quartz-saturated granulite containing relics of the peak UHT assemblage have remnant detrital cores with dates of ca. 2.5-0.83 Ga. Date clusters of ca. 1.7 and 1.04-0.83 Ga record episodes of zircon growth in the source region of the protolith sediment. Two generations of overgrowths with contrasting Th/U record metamorphic zircon growth at 569 +/- 5 and 551 +/- 7 Ma, probably in the absence and presence of monazite, respectively. The age of coexisting metamorphic monazite (547 +/- 7 Ma) is indistinguishable from that of the younger, low-Th/U zircon overgrowths. Zircon from a quartz-undersaturated monazite-absent UHT granulite with a mainly retrograde assemblage is mostly metamorphic (551 +/- 5 Ma). The ca. 570 Ma zircon overgrowths in the quartz-saturated granulite probably record partial melting just before or at the metamorphic peak. The ca. 550 Ma zircon in both rocks, and the ca. 550 Ma monazite in the quartz-saturated sample, record post-peak isothermal decompression. A possible model for this pressure-temperature-time evolution is ultrahot collisional orogeny during the assembly of Gondwana, locally superheated by basaltic underplating, followed by fast extensional exhumation.

Temperature-Sensitive Src-Transformed Mdck Cells nn 3d Cultures as a Model of Malignant Transformation of Epithelial Cells

The equilibrium between cell proliferation, differentiation, and apoptosis is crucial for maintaining homeostasis in epithelial tissues. In order for the epithelium to function properly, individual cells must gain normal structural and functional polarity. The junctional proteins have an important role both in binding the cells together and in taking part in cell signaling. Cadherins form adherens junctions. Cadherins initiate the polarization process by first recognizing and binding the neighboring cells together, and then guiding the formation of tight junctions. Tight junctions form a barrier in dividing the plasma membranes to apical and basolateral membrane domains. In glandular tissues, single layered and polarized epithelium is folded into tubes or spheres, in which the basal side of the epithelial layer faces the outer basal membrane, and the apical side the lumen. In carcinogenesis, the differentiated architecture of an epithelial layer is disrupted. Filling of the luminal space is a hallmark of early epithelial tumors in tubular and glandular structures. In order for the transformed tumor cells to populate the lumen, enhanced proliferation as well as inhibition of apoptosis is required. Most advances in cancer biology have been achieved by using two-dimensional (2D) cell culture models, in which the cells are cultured on flat surfaces as monolayers. However, the 2D cultures are limited in their capacity to recapitulate the structural and functional features of tubular structures and to represent cell growth and differentiation in vivo. The development of three-dimensional (3D) cell culture methods enables the cells to grow and to be studied in a more natural environment. Despite the wide use of 2D cell culture models and the development of novel 3D culture methods, it is not clear how the change of the dimensionality of culture conditions alters the polarization and transformation process and the molecular mechanisms behind them. Src is a well-known oncogene. It is found in focal and adherens junctions of cultured cells. Active src disrupts cell-cell junctions and interferes with cell-matrix binding. It promotes cell motility and survival. Src transformation in 2D disrupts adherens junctions and the fibroblastic phenotype of the cells. In 3D, the adherens junctions are weakened, and in glandular structures, the lumen is filled with nonpolarized vital cells. Madin-Darby canine kidney (MDCK) cells are an epithelial cell type commonly used as a model for cell polarization. Its-src-transformed variants are useful model systems for analyzing the changes in cell morphology, and they play a role in src-induced malignant transformation. This study investigates src-transformed cells in 3D cell cultures as a model for malignant transformation. The following questions were posed. Firstly: What is the role of the composition and stiffness of the extracellular matrix (ECM) on the polarization and transformation of ts v-src MDCK cells in 3D cell cultures? Secondly: How do the culture conditions affect gene expression? What is the effect of v-src transformation in 2D and in 3D cell models? How does the shift from 2D to 3D affect cell polarity and gene expression? Thirdly: What is the role of survivin and its regulator phosphatase and tensin homolog protein (PTEN) in cell polarization and transformation, and in determining cell fate? How does their expression correlate with impaired mitochondrial function in transformed cells? In order to answer the above questions, novel methods of culturing and monitoring cells had to be created: novel 3D methods of culturing epithelial cells were engineered, enabling real time monitoring of a polarization and transformation process, and functional testing of 3D cell cultures. Novel 3D cell culture models and imaging techniques were created for the study. Attention was focused especially on confocal microscopy and live-cell imaging. Src-transformation disturbed the polarization of the epithelium by disrupting cell adhesion, and sensitized the cells to their environment. With active src, the morphology of the cell cluster depended on the composition and stiffness of the matrix. Gene expression studies revealed a broader impact of src transformation than mere continuous activity of src-kinase. In 2D cultures, src transformation altered the expression of immunological, actin cytoskeleton and extracellular matrix (ECM). In 3D, the genes regulating cell division, inhibition of apoptosis, cell metabolism, mitochondrial function, actin cytoskeleton and mechano-sensing proteins were altered. Surprisingly, changing the culture conditions from 2D to 3D affected also gene expression considerably. The microarray hit survivin, an inhibitor of apoptosis, played a crucial role in the survival and proliferation of src-transformed cells.